Study On The Mechanical Behavior Of Key Tooth Joint Of Segmental Precast Assembled Concrete Beam Under Cyclic Loads

Segmental prefabricated bridge has many advantages,such as low cost,fast construction speed,easy quality control,good durability,little impact on the surrounding traffic,etc.,which are widely used in bridge engineering.The joint is the weak part of segmental prefabricated bridge,which has an important influence on the serviceability limit state and bearing capacity limit state of this kind of bridge.In order to study the mechanical behavior of key tooth joint under cyclic load,the main work and conclusions of this paper are as follows:(1)Six groups of key tooth joints are designed and manufactured,and the reciprocating load is applied to them.The failure process of the specimen is recorded in detail,and the mechanical properties of the component,such as the ultimate load,crack development,strength and stiffness degradation,and load displacement curve,are discussed under the action of cyclic load.The results are compared with the monotonic loading results of the same type of test.The ratio of single small key tooth,multiple small key teeth,large key teeth and reinforced large key teeth and steel fiber(0%,0.8%)of four key tooth types are analyzed Parameter analysis.The test results show that the ultimate bearing capacity of cyclic loading is reduced by nearly 30%compared with that of monotonic loading,and the rigidity of cyclic loading component is lower than that of monotonic loading;the mechanical performance of reinforced large key tooth component is the best,the mechanical performance of multiple small key tooth components is close to that of single key tooth component,and the number of key teeth in joint bearing capacity is not linearly reduced to some extent;the strength degradation of test component under the action of cyclic loading is unknown Obviously,adding steel fiber and reinforcing steel in the key teeth can improve the rigidity degradation of the component,and the ductility of the component with steel fiber is the best.(2)The finite element software ABAQUS is used to simulate the key tooth joint test component.The finite element results are in good agreement with the test results.The stress-strain distribution and development law of the key tooth joint are mainly analyzed.(3)Through the finite element modeling,the effects of different lateral stress,joint dry joint and adhesive joint,load application position and more key tooth shape types on the mechanical properties of key tooth joint are discussed.The results show that: the key tooth engagement depth has little effect on the bearing capacity of key tooth joint components,but the reinforcement inside the key tooth can significantly improve the key tooth performance;the stress and strain transfer of dry joint components is significantly different from that of glue joint components;with the increase of lateral stress,the ultimate bearing capacity of key tooth joint components increases;the change of load application position causes the key tooth joints to be in the form of direct shear stress The state becomes a combination of bending and shearing.